Home > Constraints on water and oxygen-bearing compounds in the lunar exosphere

Constraints on water and oxygen-bearing compounds in the lunar exosphere

Sun, 04/28/2013 - 13:36 — rkillen

We cannot explain the reported overabundance of observed O+ relative to other species (roughly 3:1 count ratio between peaks corresponding to masses 16 and 28 in Mall et al., 1998) with neutral oxygen release at levels expected from meteoritic impact vaporization of the lunar regolith or solar wind sputtering. If a lunar origin of the O+ observed is posited, volatile molecular ions such as OH+, H2O+, CO+ or CO2+ may be contributing to the O+ and C+ measured by Kaguya and WIND, a possibility suggested by Tanaka et al. [2009] that would help mitigate the model-data discrepancy for O+. However, there have been recent suggestions that OH and water can efficiently be produced by the impact of the solar wind. Alternatively, new models have shown that almost all of the interplanetary dust particles impacting the moon are composed of carbonaceous chondrites which contain up to 10 wt% water. We put limits on the both the in-situ production flux of water onto the moon, and se estimate the production of oxygen bearing compounds from impacts. W compare the resulting O+ with that measured.